Fix #18718 (#18731)

Update tests

lib/pure/stats.nim

@@ -42,7 +42,7 @@ runnableExamples:
 
   template `~=`(a, b: float): bool = almostEqual(a, b)
 
-  var statistics: RunningStat  ## Must be var
+  var statistics: RunningStat  # must be var
   statistics.push(@[1.0, 2.0, 1.0, 4.0, 1.0, 4.0, 1.0, 2.0])
   doAssert statistics.n == 8
   doAssert statistics.mean() ~= 2.0
@@ -76,7 +76,7 @@ type
 proc clear*(s: var RunningStat) =
   ## Resets `s`.
   s.n = 0
-  s.min = toBiggestFloat(int.high)
+  s.min = 0.0
   s.max = 0.0
   s.sum = 0.0
   s.mom1 = 0.0
@@ -86,11 +86,14 @@ proc clear*(s: var RunningStat) =
 
 proc push*(s: var RunningStat, x: float) =
   ## Pushes a value `x` for processing.
-  if s.n == 0: s.min = x
+  if s.n == 0:
+    s.min = x
+    s.max = x
+  else:
+    if s.min > x: s.min = x
+    if s.max < x: s.max = x
   inc(s.n)
   # See Knuth TAOCP vol 2, 3rd edition, page 232
-  if s.min > x: s.min = x
-  if s.max < x: s.max = x
   s.sum += x
   let n = toFloat(s.n)
   let delta = x - s.mom1

tests/stdlib/tstats.nim

@@ -1,46 +1,55 @@
-include stats
+import std/stats
 
-proc clean(x: float): float =
-  result = round(1.0e8*x).float * 1.0e-8
+proc `~=`(x, y: float): bool =
+  abs(x - y) < 10e-8
 
-var rs: RunningStat
-rs.push(@[1.0, 2.0, 1.0, 4.0, 1.0, 4.0, 1.0, 2.0])
-doAssert(rs.n == 8)
-doAssert(clean(rs.mean) == 2.0)
-doAssert(clean(rs.variance()) == 1.5)
-doAssert(clean(rs.varianceS()) == 1.71428571)
-doAssert(clean(rs.skewness()) == 0.81649658)
-doAssert(clean(rs.skewnessS()) == 1.01835015)
-doAssert(clean(rs.kurtosis()) == -1.0)
-doAssert(clean(rs.kurtosisS()) == -0.7000000000000001)
+template main() =
+  var rs: RunningStat
+  rs.push(@[1.0, 2.0, 1.0, 4.0, 1.0, 4.0, 1.0, 2.0])
+  doAssert(rs.n == 8)
+  doAssert rs.mean ~= 2.0
+  doAssert rs.variance() ~= 1.5
+  doAssert rs.varianceS() ~= 1.71428571
+  doAssert rs.skewness() ~= 0.81649658
+  doAssert rs.skewnessS() ~= 1.01835015
+  doAssert rs.kurtosis() ~= -1.0
+  doAssert rs.kurtosisS() ~= -0.7000000000000001
 
-var rs1, rs2: RunningStat
-rs1.push(@[1.0, 2.0, 1.0, 4.0])
-rs2.push(@[1.0, 4.0, 1.0, 2.0])
-let rs3 = rs1 + rs2
-doAssert(clean(rs3.mom2) == clean(rs.mom2))
-doAssert(clean(rs3.mom3) == clean(rs.mom3))
-doAssert(clean(rs3.mom4) == clean(rs.mom4))
-rs1 += rs2
-doAssert(clean(rs1.mom2) == clean(rs.mom2))
-doAssert(clean(rs1.mom3) == clean(rs.mom3))
-doAssert(clean(rs1.mom4) == clean(rs.mom4))
-rs1.clear()
-rs1.push(@[1.0, 2.2, 1.4, 4.9])
-doAssert(rs1.sum == 9.5)
-doAssert(rs1.mean() == 2.375)
+  var rs1, rs2: RunningStat
+  rs1.push(@[1.0, 2.0, 1.0, 4.0])
+  rs2.push(@[1.0, 4.0, 1.0, 2.0])
+  let rs3 = rs1 + rs2
+  doAssert rs3.variance ~= rs.variance
+  doAssert rs3.skewness ~= rs.skewness
+  doAssert rs3.kurtosis ~= rs.kurtosis
+  rs1 += rs2
+  doAssert rs1.variance ~= rs.variance
+  doAssert rs1.skewness ~= rs.skewness
+  doAssert rs1.kurtosis ~= rs.kurtosis
+  rs1.clear()
+  rs1.push(@[1.0, 2.2, 1.4, 4.9])
+  doAssert(rs1.sum == 9.5)
+  doAssert(rs1.mean() == 2.375)
 
-when not defined(cpu32):
-  # XXX For some reason on 32bit CPUs these results differ
-  var rr: RunningRegress
-  rr.push(@[0.0, 1.0, 2.8, 3.0, 4.0], @[0.0, 1.0, 2.3, 3.0, 4.0])
-  doAssert(rr.slope() == 0.9695585996955861)
-  doAssert(rr.intercept() == -0.03424657534246611)
-  doAssert(rr.correlation() == 0.9905100362239381)
-  var rr1, rr2: RunningRegress
-  rr1.push(@[0.0, 1.0], @[0.0, 1.0])
-  rr2.push(@[2.8, 3.0, 4.0], @[2.3, 3.0, 4.0])
-  let rr3 = rr1 + rr2
-  doAssert(rr3.correlation() == rr.correlation())
-  doAssert(clean(rr3.slope()) == clean(rr.slope()))
-  doAssert(clean(rr3.intercept()) == clean(rr.intercept()))
+  when not defined(cpu32):
+    # XXX For some reason on 32bit CPUs these results differ
+    var rr: RunningRegress
+    rr.push(@[0.0, 1.0, 2.8, 3.0, 4.0], @[0.0, 1.0, 2.3, 3.0, 4.0])
+    doAssert(rr.slope() == 0.9695585996955861)
+    doAssert(rr.intercept() == -0.03424657534246611)
+    doAssert(rr.correlation() == 0.9905100362239381)
+    var rr1, rr2: RunningRegress
+    rr1.push(@[0.0, 1.0], @[0.0, 1.0])
+    rr2.push(@[2.8, 3.0, 4.0], @[2.3, 3.0, 4.0])
+    let rr3 = rr1 + rr2
+    doAssert(rr3.correlation() == rr.correlation())
+    doAssert rr3.slope() ~= rr.slope()
+    doAssert rr3.intercept() ~= rr.intercept()
+
+  block: # bug #18718
+    var rs: RunningStat
+    rs.push(-1.0)
+    doAssert rs.max == -1.0
+
+static: main()
+main()